For example, air-conditioning apparatuses exist that exchange heat between a heat-source-side refrigerant that circulates through a refrigeration cycle (refrigerant circuit) configured by connecting, by pipes, an outdoor unit and a relay unit, and an indoor-side refrigerant (heat medium) that circulates through a heat medium circuit configured by connecting, by pipes, the relay unit and an indoor unit. In addition, in applying an air-conditioning apparatus having such a configuration to a multi-air-conditioning apparatus for buildings or the like, for example, an apparatus exists which achieves energy saving by reducing the conveyance power for a heat medium (see, for example, Patent Literature 1). As described above, arranging two circulation circuits allows water or the like, which does not adversely affect health or the like of users inside a building, to be used as a refrigerant for a heat medium which circulates inside the building.